CN108957780B

CN108957780B - Optical element and display device using same

Info

Publication number: CN108957780B
Application number: CN201710351555.4A
Authority: CN
Inventors: 张馨文; 林弘裕; 陈永彬
Original assignee: Cm Visual Technology Corp
Current assignee: Cm Visual Technology Corp
Priority date: 2017-05-18
Filing date: 2017-05-18
Publication date: 2020-11-24
Anticipated expiration: 2037-05-18
Also published as: CN108957780A

Abstract

The invention discloses an optical element and a display device using the sameArranged along at least one group of first tracks in a first direction, wherein the first tracks have a first period T₁And a first amplitude A₁The waveform trace of (2).

Description

Optical element and display device using same

Technical Field

The present invention relates to an optical element and a display, and more particularly, to an optical element for deflecting light and a display device using the optical element.

Background

The conventional display comprises a plurality of structures arranged according to a specific period, and if the microstructures of the optical film applied to the display are also arranged according to the specific period, the two periodic structures generate Moire (Moire pattern) of interference phenomenon, which seriously affects the display effect. Therefore, there is a need to develop optical films that can improve moir é.

Disclosure of Invention

The invention discloses an optical element and a display device using the same, which are used for eliminating Moire fringes generated by structural interference of periodic arrangement.

According to an aspect of the present invention, an optical device is provided, which includes a plurality of light deflecting regions arranged along at least one set of first tracks in a first direction, wherein the first tracks have a first period T₁And a first amplitude A₁The waveform trace of (2).

According to an aspect of the present invention, an optical element is provided, which includes a film layer and a plurality of light deflecting regions. The light deflection areas are arranged on the film layer and respectively comprise two or more than two periodic diffraction structures.

According to an aspect of the present invention, a display device is provided, which includes a display and an optical element disposed on a light-emitting side of the display.

In order that the manner in which the above recited and other aspects of the present invention are obtained can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the appended drawings, in which:

drawings

FIG. 1A is a schematic diagram of a display device and optical elements thereof according to an embodiment of the invention;

FIG. 1B is a schematic illustration of four embodiments of an optical element;

FIGS. 2A and 2B are diagrams of light deflecting regions arranged along a track in a first directionColumn diagram and region S₁Is shown in enlarged schematic view;

FIGS. 3A and 3B are schematic diagrams of light deflecting regions arranged along a track in first and second directions and regions S₂Is shown in enlarged schematic view;

FIGS. 4A and 4B are schematic diagrams of two sets of light deflecting regions arranged along a track;

FIGS. 5A and 5B are schematic diagrams of two sets of light deflecting regions arranged along a track in a staggered manner;

FIGS. 6A and 6B are schematic diagrams of three sets of light deflecting regions arranged along a track and partially overlapping;

FIG. 7A is a diagram of a diffractive structure having a single period;

FIGS. 7B to 7E are schematic diagrams of diffractive structures comprising two or more periods;

FIGS. 8A-8C are schematic side views of the diffraction structures showing gradual variation of period (or density) and amplitude;

FIGS. 9A-9D are schematic diagrams of full widths at half maximum of four different types of diffractive structures.

Description of the symbols

1: display device

10: display device

20: optical element

21a to 21 d: first pattern

22: light deflecting region

23: track of

24: light deflecting region

25: track of

A₁: first amplitude

A₂: second amplitude

D₁、D₂: characteristic dimension

T₁: first period

T₂: second period

32: circular light deflecting area

33. 35: track of

34: circular light deflecting area

36: square light deflection area

P₁: first track gauge

P₂: second track gauge

P₃: third track pitch

P₄: fourth track pitch

42a, 42 b: light deflecting region

43a, 43b, 45a, 45 b: track of

52: light deflecting region

53a to 53 e: diffraction structure

63a, 63b, 63 c: diffraction structure

T₅: first period

T₆: second period

T₇: the third period

w₁、w₂: period of time

h₁、h₂: amplitude of vibration

72 a: square wave diffraction structure

72 b: sawtooth diffraction structure

72 c: sine wave diffraction structure

72 d: bevel-shaped diffraction structure

w: full width at half maximum

T_g: period of time

θ: zenith angle

Psi: azimuth angle

S₁、S₂: local area

Detailed Description

The following embodiments are provided for illustrative purposes only and are not intended to limit the scope of the present invention.

Referring to fig. 1A, a display device 1 includes a display 10 and an optical element 20. The optical element 20 is arranged on the light exit side of the display 10 to display an image. The display 10 may be a liquid crystal display, a plasma display, an organic light emitting diode display, an electronic paper display, or other displays for displaying images. Meanwhile, the display 10 may be combined with other elements (for example, a touch panel formed by disposing a touch element), and the optical element 20 may be disposed on the light emitting side of the display 10 along with other elements (for example, an anti-reflection film, a touch panel).

The optical element 20 may be a film with a light deflecting structure for deflecting light emitted from the display 10. Using the concept of a spherical coordinate system, two mutually perpendicular lines are selected as coordinate axes on a plane parallel to the display surface of the display 10, generally a horizontal line pointing to the right is referred to as an X axis, a vertical line pointing to the upper direction is referred to as a Y axis, and an axis perpendicular to the display surface of the display 10 is defined as a Z axis, so that the viewing angle for viewing the display 10 can be expressed by a zenith angle θ and an azimuth angle ψ in the spherical coordinate system. Wherein psi is an azimuth angle which is an angle between the X-axis and the Y-axis in the X-axis and Y-axis plane, and the azimuth angle psi can be from 0 degree to 360 degrees. The zenith angle theta is an angle formed by the zenith angle theta and the Z axis, and the zenith angle theta can be from +90 degrees to-90 degrees. The included angle between any two directions is represented by taking the included angle in the anticlockwise direction as positive and taking the included angle in the clockwise direction as negative. In one embodiment, an axis parallel to the horizontal line is defined as the X-axis, an axis parallel to the plumb line is defined as the Y-axis, and a third coordinate of a plane perpendicular to the X-axis and the Y-axis is defined as the Z-axis.

Referring to fig. 1A and 1B, in an embodiment, the optical element 20 includes at least one light-deflecting region and a general region (non-light-deflecting region) outside the light-deflecting region. The light-deflecting area can cause the high-deflecting effect that the ratio of the zero-order deflection (direct emergent) light intensity and the non-zero-order deflection (emergent direction changed) light intensity is lower than 100 for the light penetrating in a specific direction, and the general area (or the non-light-deflecting area) causes the low-deflecting effect that the ratio of the zero-order deflection (direct emergent) light intensity and the non-zero-order deflection (emergent direction changed) light intensity is higher than 100 for the penetrating light, so as to enhance the light transmission amount. Alternatively, the "general region" (or non-light-deflecting region) can have the same effect as the "non-light-deflecting region"), in which light hardly passes through, i.e., the non-light-transmitting region.

Referring to fig. 1B, the optical element 20 includes a first pattern formed by arranging light-deflecting regions, which may be formed by a process such as imprinting, stamping, transferring or printing. The first pattern is a pattern formed by a distribution range of the light-deflecting region, and various embodiments are possible, and only 4 patterns are listed below as conceptual examples. In the first embodiment (1), the light-deflecting regions are uniformly distributed over the entire optical element 20, that is, the first pattern 21a is equal to the specification size of the optical element 20; in the second embodiment (2), the light deflection regions are distributed inside the optical element 20, and the outer periphery of the non-light deflection region is formed on the optical element 20. In this embodiment, the first pattern 21b is smaller than the specification size of the optical element 20; in the third embodiment (3), the first patterns 21c are smaller than the size of the optical element 20 in a direction (e.g., a direction parallel to the Y axis in the figure), and form two or more groups of interval arrangement in the direction, and the arrangement may have periodicity; in the fourth embodiment (4), the first patterns 21d are smaller than the optical element 20 in two directions (e.g., the directions parallel to the X-axis and the Y-axis in the figure), and may be arranged at intervals of two or more groups along one direction, and the arrangement may be periodic. In summary, the light deflecting area may occupy 30-100% of the area of the optical element. In one embodiment, the light deflecting region occupies more than 90% of the area of the optical element, for example: the light deflection area accounts for 95-100% of the area of the optical element. It should be noted that the edge of the first pattern may be a straight line or a wavy curve, and the wavy trajectory is exemplified in the above-described embodiments (2) to (4).

In one embodiment of the present description, the light-deflecting regions in the first pattern may be arranged along a periodic function in the first direction, that is, the light-deflecting regions are arranged on at least one periodic track. Alternatively, in another embodiment, the light deflecting regions of the first pattern may be arranged along a first periodic function in a first direction and along a second periodic function in a second direction different from the first direction, i.e. the light deflecting regions are arranged at the intersection of two periodic tracks. The periodic function may be a waveform function, for example. For example, the light deflecting regions may be arranged along a first wave-shaped track in a direction parallel to the X-axis, wherein the first wave-shaped trackWith a fixed period T₁And a fixed amplitude A perpendicular to the X-axis₁(ii) a Alternatively, the light deflecting regions may be arranged along a first waveform trace in a direction parallel to the X-axis and a second waveform trace having a fixed period T in a direction parallel to the Y-axis₂And a fixed amplitude A perpendicular to the Y-axis₂. However, the first and second waveform traces may have a varying period or a varying amplitude, which is not limited by the present invention.

The following explains a possible arrangement of the light deflecting regions with reference to the drawings. Fig. 2A and fig. 3A show an example of an arrangement of a portion of the light-deflecting region 22 on the optical element 20, wherein a blank portion indicates that the light-deflecting region 22 is omitted or a non-light-deflecting region without light-deflecting effect is omitted. In detail, the optical element 20 has a plurality of

light deflecting regions

22 and 24, and a pattern formed by the arrangement of the

light deflecting regions

22 and 24 is a first pattern. The light-deflecting region may be circular, elliptical or polygonal, such as triangular, square, quadrilateral, pentagonal or hexagonal, etc. The light deflecting region has a characteristic dimension D₁If the light-deflecting area is circular, its characteristic dimension D₁Defined as the diameter; if the light-deflecting area is polygonal, the characteristic dimension D₁The circumscribed circle diameter defined as a polygon; if the light-deflecting area is elliptical, the characteristic dimension D₁Defined as the arithmetic mean of the major and minor axes; in other embodiments, similar pattern feature size definitions may be used depending on the shape of the light deflecting region. In one embodiment, the feature size D₁Can be 4-80 microns, such as 30-60 microns or about 20-70 microns. The light deflecting region may occupy 30% to 100% of the area of the optical element.

In one embodiment, referring to fig. 2A and 2B, the light deflecting regions 22 are arranged along the track 23 in a first direction (e.g., an azimuth angle ψ is 0 or a direction parallel to the X axis), and the track 23 has a first period T₁And a first amplitude A₁Wherein the first period direction is parallel to the first direction (direction parallel to the X-axis), and the first amplitude direction is perpendicular to the first direction (direction perpendicular to the X-axis). Here a first period T₁Is the peak-to-peak (or valley-to-valley) distance, and the first amplitude A₁The distance from the position of the balance point to the wave crest or the wave trough is half of the distance from the wave crest to the wave trough. The trace 23 may be functionally represented as

In one embodiment, the first amplitude A₁And a first period T₁Characteristic dimension D of light deflecting region 22, which may be greater than or equal to two times₁That is to say A₁≥2D₁And T₁≥2D₁. Furthermore, the first amplitude A₁And a first period T₁Can be greater than zero and less than or equal to 10, that is to say 0 <

In another embodiment, A₁≥5D₁And T₁≥10D₁. For example, diameter D of circular light-deflecting region 22 of FIGS. 2A and 2B₁At 30 μm, a first amplitude A₁E.g., 1 millimeter (mm), first period T₁For example, 1 millimeter (mm). In this embodiment, the light deflecting regions 22 are aligned along a straight line in a second direction (e.g., an azimuth angle ψ of 90 or a direction parallel to the Y-axis).

In another embodiment, referring to fig. 3A and 3B, the

light deflecting regions

22 and 24 are arranged along the track 25 in a second direction (e.g., the azimuth angle ψ is 90 or a direction parallel to the Y axis) in addition to the first direction (e.g., the direction parallel to the X axis) along the track 23, i.e., the

light deflecting regions

22 and 24 are arranged at the intersection of the track 23 and the track 25. Trace 25 has a second period T₂And a second amplitude A₂Wherein the second periodic direction is parallel to the second direction (direction parallel to the Y-axis) and the second amplitude direction is perpendicular to the second direction (direction perpendicular to the Y-axis). Here the second period T₂Peak to peak (or trough to trough) distance, and a second amplitude A₂The distance from the position of the balance point to the wave crest or the wave trough is half of the distance from the wave crest to the wave trough. The trace 25 may be functionally represented as

In one embodiment, the second amplitude A₂And a second period T₂Characteristic dimension D of

light deflecting regions

22 and 24 that may be greater than or equal to two times₁That is to say A₂≥2D₁And T₂≥2D₁. In addition, the second amplitude A₂And a second period T₂Can be greater than zero and less than or equal to 1, that is to say

For example, diameter D of circular light-deflecting region 22 of FIGS. 3A and 3B₁At 30 μm, a first amplitude A₁E.g., 1 millimeter (mm), first period T₁E.g., 1 millimeter (mm), second amplitude a₂E.g., 0.1 millimeters (mm), second period T₂For example, 3 millimeters (mm). In one embodiment, the first amplitude A₁And a first period T₁Is greater than the second amplitude A₂And a second period T₂The ratio of (a) to (b), that is,

the larger the value of (A), the longer the period T₁Amplitude of A₁The steeper the track 23 is, the

The smaller the value of (A), the shorter the period is T₂Amplitude of A₂The more gradual the trajectory 25.

In one embodiment, the light deflecting regions are arranged along the track 23 in a direction having an azimuth angle ψ of 0 ± 20 degrees and arranged along the track 25 in a direction having an azimuth angle ψ of 90 ± 20 degrees, that is, the directions of the track 23 and the track 25 are different, and the angle between the track 23 and the track 25 may be between 50 and 130 degrees. In another embodiment, the light deflecting regions are arranged along the track 23 in a direction having an azimuth angle ψ of 45 ± 30 degrees and arranged along the track 25 in a direction having an azimuth angle ψ of 135 ± 30 degrees, i.e. the angle between the track 23 and the track 25 may be between 30 and 150 degrees. Therefore, the display device 1 of the present invention can adjust the azimuth angles of the

tracks

23 and 25 of the first pattern on the optical element 20 according to actual requirements to generate different deflection effects.

In one embodiment, the track 23 is, for example, a sine function or an approximate sine function, but may also include a plurality of periodic functions, and is not limited to only one periodic function, but may also be a sum of a plurality of periodic functions. If the function of the trace 23 is obtained by adding a plurality of periodic functions with the same period, the period of the trace 23 is still the same, and if the function of the trace 23 is obtained by adding a plurality of periodic functions with different periods, the period of the trace 23 is the least common multiple of the periods, for example, the function with the period of 2 pi is added to the function with the period of 3 pi, and the function with the period of 6 pi can be obtained. Likewise, the same is true of the traces 25, which are not described in detail herein. Thus, the above-mentioned

tracks

23, 25 can be obtained by adding periodic functions of the same or different periods, given a Fourier series f (t) consisting of sine and/or cosine functions, t ∈ [ - π, π]，a_n、b_nFor amplitude, the following formula is available:

in order to simplify the drawing, the following figures are illustrated with patterns in which only a portion of the light-deflecting regions are arranged. In an embodiment, referring to fig. 4A, taking 8 circular light-deflecting regions 32 as an example, the circular light-deflecting regions 32 are arranged on the track 33 in two adjacent groups and four in each group in the first direction (azimuth angle ψ is 0), and in four adjacent groups and two in each group in the second direction (azimuth angle ψ is 90). Wherein the tracks 33 of adjacent groups are at a first track pitch P in the second direction₁The components are arranged at intervals; the straight lines M of the adjacent four groups have a second track pitch P along the first direction₂Are arranged at intervals.

In another embodiment, referring to fig. 4B, taking 8 square light-deflecting regions 36 as an example, the square light-deflecting regions 36 are arranged on the track 33 in two adjacent groups and four in each group in the first direction (azimuth angle ψ ═ 0), and in four adjacent groups and two in each group in the second direction (azimuth angle ψ ═ 70)On the straight line M. Wherein the tracks 33 of adjacent groups are at a first track pitch P in the second direction₁The components are arranged at intervals; the straight lines M of the adjacent four groups have a second track pitch P along the first direction₂Are arranged at intervals.

As can be seen from the above embodiments, the light-deflecting regions are arranged on a first track in a first direction and on a second track in a second direction. Wherein the first track has a first track pitch P₁Spaced apart, i.e. first track pitch P₁Is the distance closest to the two first tracks and the first track pitch P₁Characteristic dimension D of light deflection region₁Can be expressed as 0.1D₁≤P₁≤25D₁(ii) a Furthermore, the second track has a second track pitch P₂Spaced apart, i.e. second track pitch P₂Is the distance closest to the two sets of second tracks with the second track pitch P₂Characteristic dimension D of light deflection region₁Can be expressed as 0.1D₁≤P₂≤25D₁. In other embodiments, the first gauge P₁And a second track pitch P₂The ratio of (a) may be 0.1 or more, 10 or less, that is,

in the foregoing embodiment, the first gauge P₁Characteristic dimension D of light deflection region₁Is 0.5D₁≤P₁≤10D₁(ii) a Second track gauge P₂Characteristic dimension D of light deflection region₁Is 0.5D₁≤P₂≤10D₁. When there are more than two groups of light deflection regions, the first track pitch P₁And a second track pitch P₂The track gauge can be a fixed value or a variable value, and can be adjusted according to actual requirements, and the following track gauge concept is similar to the fixed value and is not repeated.

Since the circular light-deflecting regions 32 are arranged along the tracks 33, even if the circular light-deflecting regions 32 are overlapped with the periodically arranged pixel structures, the partial circular light-deflecting regions 32 are misaligned (do not correspond to each other in position) with respect to the partial pixel structures, and thus moire (or ghost) that is not easily interfered is generated, and thus the display effect is not affected. Similarly, referring to fig. 4B, the square light-deflecting regions 36 arranged along the track 33 also have the same interference prevention effect. The anti-interference effect of the following embodiments is similar to that of the above embodiments, and the description is not repeated.

Referring to fig. 5A, 10 circular light-deflecting regions 32 are taken as an example, which is different from fig. 4A in that: the circular light deflecting regions 32 are arranged on the track 33 in two adjacent groups of five in the first direction (azimuth angle psi ═ 0), on the track 35 in the second direction (azimuth angle psi ═ 70), and the track 33 and the track 35 have an included angle of 30-150 degrees, and the first track pitch P is₁And a second track pitch P₂The ratio of (a) may be 0.1 or more, 10 or less, that is,

in this embodiment, the first gauge P₁Characteristic dimension D of light deflection region₁Is 1.1D₁≤P₁≤20D₁(ii) a Second track gauge P₂Characteristic dimension D of light deflection region₁Is 1.1D₁≤P₂≤20D₁The light deflecting regions 32 are separated from each other and do not overlap. Similarly, referring to fig. 5B, the square light-deflecting regions 36 arranged along the

tracks

33, 35 may also have the arrangement described above.

In one embodiment, when

Is less than 1 and/or

When the value of (a) is less than 1, it means that at least two sets of circular light-deflecting regions 32 are partially overlapped, and when two sets of circular light-deflecting regions 32 are partially overlapped, the overlapping portion and the non-overlapping portion may have different patterns (i.e. the first pattern and the second pattern having different shapes or different conditions), so that the deflecting effect of the overlapping portion and the deflecting effect of the non-overlapping portion may be different. For example, two layers of the optical element 20 are stacked, wherein the first pattern isWhen the circular light-deflecting regions 32 are at least partially overlapped with the circular light-deflecting regions 32 of the second pattern, when the stacked structure formed by the multi-layered optical element 20 is irradiated by a light source, not only the penetrating light in the deflecting direction of the single-layered optical element 20 but also the penetrating light in other deflecting directions (e.g., oblique directions) are generated, thereby improving the deflecting effect.

Referring to fig. 6A, taking 12 circular light-deflecting

regions

42a, 42b, and 42c as an example, 4 circular light-deflecting

regions

42a, 4 circular light-deflecting

regions

42b, and 4 circular light-deflecting regions 42c are respectively arranged on three tracks 43a in a first direction (azimuth angle ψ 0) in four rows, and on four straight lines M in a second direction (azimuth angle ψ 90) in three columns. Wherein the tracks 43a of three adjacent tracks have a first track pitch P₁The components are arranged at intervals; the adjacent four straight lines M have a second track pitch P₂Are arranged at intervals. It should be noted that the

light deflecting regions

42a, 42b and 42c may each have the same or different size or shape, with a circular shape being merely exemplary in this embodiment; the

light deflecting regions

42a, 42b and 42c may be arranged along the same or different tracks in the first direction and the second direction, respectively, and only the same track 43a and the straight line M are taken as an example in this embodiment.

Light deflecting regions

42a, 42b, and 42c may be separate from or at least partially overlap each other, in this embodiment light deflecting region 42a at least partially overlaps light deflecting region 42b, and light deflecting region 42b at least partially overlaps light deflecting region 42c, where light deflecting region 42b is located between light deflecting region 42a and light deflecting region 42 c. In this embodiment, the first track pitch P between two adjacent sets of tracks 43a₁Less than a characteristic dimension D₁(P₁<D₁) Such that the light-deflecting regions on each track 43a at least partially overlap each other. In another embodiment, the first track pitch P between two adjacent tracks 43a₁And a second track pitch P between two adjacent straight lines M₂Are all less than the characteristic dimension D₁(P₁<D₁And P is₂<D₁) So that the light-deflecting regions on each track 43a and each straight line M are at least partially overlapped. The light-deflecting region here may be formed on a single optical layer; alternatively, the first and second electrodes may be,the light deflecting region here may be a multilayer light deflecting region formed by stacking a plurality of layers (two or more layers) of the optical elements 20. For example,

light deflecting regions

42a and 42c are located on one film layer of optical element 20 to form a first pattern, and light deflecting regions 42b are located on another film layer of optical element 20 to form a second pattern, where the first pattern and the second pattern may have the same track or different tracks.

In addition, referring to fig. 6B, two types of light deflecting regions 42a and 42B are taken as an example: the light deflecting regions 42a are arranged on the track 43a in adjacent two rows and four in each row in the first direction (azimuth angle ψ 0), and on the track 45a in adjacent four columns and two in each column in the second direction (azimuth angle ψ 90); the light deflecting regions 42b are arranged on the track 43b in two adjacent rows and three in each row in the first direction (azimuth angle ψ 0), and on the track 45b in three adjacent columns and two in each column in the second direction (azimuth angle ψ 90); wherein the track 43a is at a first track pitch P₁The components are arranged at intervals; said locus 45a is at a second gauge P₂Spaced apart, said tracks 43b being at a third pitch P₃The components are arranged at intervals; the track 45b is at a fourth pitch P₄Are arranged at intervals. In one embodiment, the first gauge P₁Different from the third track pitch P₃And/or a second gauge P₂Different from the fourth track pitch P₄. In one embodiment, the characteristic dimension D of the light deflecting region 42b₂Greater or less than characteristic dimension D of light deflecting region 42a₁. In another embodiment, the characteristic dimension D of the light deflecting region 42b₂Equal to the characteristic dimension D of the light-deflecting region 42a₁. According to the track gauge P₁、P₂、P₃And P₄And a characteristic dimension D₁And D₂The relative relationship of the

light deflecting regions

42a and 42b determines the separation or at least partial overlap of the light deflecting regions with each other. For example, when the first track gauge P₁And/or a third gauge P₃Is less than D₁+D₂Time, or second gauge P₂And/or a fourth track gauge P₄Is less than D₁When the light-deflecting regions partially overlap, a situation may occur. The light deflecting region may be formed in a single lightOn the chemical layer; alternatively, the light-deflecting region may be a multilayer light-deflecting region formed by stacking a plurality of (two or more) optical elements 20. For example, the light-deflecting region 42a is located on one film layer of the optical element 20 to form a first pattern, and the light-deflecting region 42b is located on another film layer of the optical element 20 to form a second pattern, and the first pattern and the second pattern may have the same track or different tracks.

The light deflecting region can be a diffractive structure with a deflecting effect, as illustrated below. The light deflecting region may include a single periodic arrangement of diffractive structures. Referring to fig. 7A, the light deflecting area 52 includes a single periodically arranged diffraction structure 53a, such as: the diffraction structure 53a is a grating structure having a single period. The light deflecting region may also include a diffractive structure with varying periods (or multiple periods), i.e., the diffractive structure may include grating structures with two or more periods. Referring to fig. 7B to 7E, the diffraction structures 53B to 53E are grating structures with multiple periods, and the variation range of the grating period is, for example, between 0.4 to 10 μm.

In one embodiment, the diffraction structure of the light deflecting area includes at least 2 grating groups, each grating group has at least 1 grating unit, and the grating units in the same grating group have the same grating period. If the maximum grating period in each grating group in the diffraction structure is defined as C, the variation between the grating periods in the two closest grating groups is at least 1% of the maximum grating period C or less than 90% of the maximum grating period C. For example, when the maximum grating period is 2 microns, the variation between grating periods in the two closest sets of gratings is at least 0.02 microns or less than 1.8 microns. In another embodiment, if the variation between the maximum grating period and the minimum grating period in the diffraction structure is defined as Δ C, the variation between the grating periods in the two closest grating groups is 5% -100% of the variation Δ C. For example, when the variation Δ C between the maximum grating period and the minimum grating period is 1.2 microns, the variation between the grating periods in the two closest sets of gratings is 0.06-1.2 microns.

FIG. 7B &' sFig. 7E illustrates an embodiment of the light deflecting region, in which a stripe grating is used as the grating unit. In fig. 7B, the light deflecting area 52 has 20 grating groups, each grating group has one grating strip, and the grating groups are arranged along a single direction with a gradually varying period to form the diffraction structure 53B. For example, the grating period may be defined by a first period T₅(e.g., 0.8 microns) is ramped up to a second period T₆(e.g., 2.0 microns) to form diffractive structures 53b having a density of grating cells that is graded from dense to dense. In this embodiment, the grating period of each grating strip is different, and therefore, the period is defined as a gradual period. In fig. 7C, the diffractive structure 53C of the light deflecting area 52 has 3 grating groups, each having 3-6 grating strips, and the grating periods of the grating groups are arranged in an increasing manner along a single direction. For example, the grating period may be increased from a first period T5 (e.g., 0.8 microns) to a second period T₆(e.g., 1.3 microns) and then a second period T₆Increased to a third period T₇(e.g., 2.0 microns) to form diffractive structures 53c having a density of grating cells that is graded from dense to dense. In fig. 7D, the light deflecting area 52 has 10 grating groups, each grating group has 1 grating strip, and the grating groups form a diffraction structure 53D in a bidirectional gradient periodic arrangement. For example, the grating period may be defined by a first period T₅(e.g., 2.0 microns) taper to a second period T₆(e.g., 0.8 microns) and then a second period T₆Is gradually increased to a third period T₇(e.g., 2.0 or 1.3 microns) to form diffractive structures 53d (dense in the middle, sparse on both sides) with grating cell density first sparse and dense second sparse. In fig. 7E, the light deflecting area 52 has 10 grating groups, each grating group has 1 grating strip, and the grating groups form a diffraction structure 53E in a bidirectional gradient periodic arrangement. For example, the grating period may be defined by a first period T₅(e.g., 0.8 microns) is ramped up to a second period T₆(e.g., 2.0 microns) and then a second period T₆Gradually decrease to a third period T₇(e.g., 0.8 or 1.3 microns) to form a grating cell density first dense to sparse and then dense to dense diffractive structures 53e (middle sparse, two sides dense).

In the present embodiment, the diffraction structures 53b to 53e having varying periods have the advantage of not easily generating moire (or ghost) interference, compared to the diffraction structure 53a arranged in a single period, and do not affect the display effect.

In other embodiments, moire can also be improved by adjusting the ratio of grating period to amplitude. As mentioned above, the diffractive structure of the light deflecting area may include a plurality of grating units with different grating periods, and the relationship between the grating period and the amplitude is illustrated by the diffractive structure with a gradually-changed period. Referring to fig. 8A and 8B, schematic side views of the diffraction structures 63a and 63B showing gradual changes in period (or density) and amplitude are shown. In fig. 8A, when the period of the grating unit in the diffractive structure 63a decreases from the center of the diffractive structure 63a to the two sides, the amplitude of the grating unit may decrease from the center of the diffractive structure 63a to the two sides. In fig. 8B, when the period of the grating unit in the diffractive structure 63B increases from the center of the diffractive structure 63a to the two sides, the amplitude of the grating unit can increase from the center of the diffractive structure 63a to the two sides. Wherein, w₁And h₁Represents the period and amplitude of the grating elements in the central area of the

diffractive structure

63a, 63b, and w₂And h₂Indicating the period and amplitude of the grating elements approaching in both lateral directions. In the above two embodiments, the period w of the grating unit in the central region₁Can be larger or smaller than the period w of the grating units approaching to both sides₂I.e. w₁>w₂Or w₁<w₂. Furthermore, the amplitude h of the grating elements of the central zone₁Can be larger or smaller than the amplitude h of the grating units approaching to the two sides₂I.e. h₁>h₂Or h₁<h₂. In one embodiment, the aspect ratio of the grating units in the central region is amplitude h₁And period w₁The ratio of (a) to (b) can range from 0.1 to 10, and the aspect ratio of the grating units approaching to both sides is the amplitude h₂And period w₂The ratio of (a) to (b) can range from 0.1 to 10. When in use

Is equal to

The numerical values of (a) and (b) indicate that the periods and amplitudes of the grating units in the

diffraction structures

63a and 63b are both gradually changed (e.g., gradually increased or decreased) in equal proportion from the center to the two sides. Thus, the period and amplitude of the grating unit can be changed to further change the deflection effect of the

diffractive structures

63a, 63 b.

Referring to fig. 8C, the period and amplitude of the grating units in the diffractive structure 63C can also gradually change from one side of the diffractive structure 63C to the other side. In one embodiment of the present invention, the substrate is,

is, for example, 0.5, and

the value of (b) is, for example, 0.5. When in use

Is equal to

The values of (a) and (b) indicate that the period and amplitude of the grating unit in the diffraction structure 63c are both gradually changed (e.g., gradually increased or decreased) from one side to the other side in an equal proportion. Thus, the period and amplitude of the grating units in the diffractive structure 63c can be changed, so as to further change the deflection effect of the diffractive structure 63 c.

Referring to fig. 9A to 9D, fig. 9A is a schematic diagram of the full width at half maximum of the square-wave diffraction structure 72a, fig. 9B is a schematic diagram of the full width at half maximum of the sawtooth-shaped diffraction structure 72B, fig. 9C is a schematic diagram of the full width at half maximum of the sine-wave diffraction structure 72C, and fig. 9D is a schematic diagram of the full width at half maximum of the sawtooth-shaped diffraction structure 72D. Wherein, T_gThe period of the diffraction structure is shown as a single period, and w represents the width at which the amplitude is 1/2 of the full height amplitude (i.e., full width at half maximum). In one embodiment, the full width at half maximum w and the period T_gThe ratio of (A) to (B) may be between 0.1 and 0.9. In summary, the waveform of the diffraction structure and the half of the diffraction structure can be changedThe mode of high full width changes the deflection effect of the diffraction structure.

The optical element and the display device using the same disclosed in the above embodiments of the present invention utilize the light-deflecting regions arranged along the waveform tracks to eliminate moire patterns generated by the periodically arranged patterns, so that the display effect of the display device is not affected. In addition, the invention can eliminate Moire fringes caused by periodically arranged patterns by utilizing the diffraction structure with the periodically arranged change, thereby not influencing the display effect of the display device.

In summary, although the present invention has been disclosed in connection with the above preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the definition of the appended claims.

Claims

1. An optical element, comprising:

a first pattern comprising:

a plurality of light deflecting regions arranged along at least one set of first tracks in a first direction, wherein the first tracks have a first period T₁And a first amplitude A₁The trajectory of the waveform of (a) is,

the light deflecting regions have a characteristic dimension D and T₁、A₁And D satisfies the following formula:

(1)A₁≥2D；

(2)T₁not less than 2D; and

(3)

2. the optical element of claim 1, wherein the first track is a sinusoidal function or a fourier series consisting of a plurality of sinusoidal functions.

3. The optical element of claim 1, wherein the light-deflecting regions are arranged along at least one set of second tracks in a second direction, wherein the first direction is different from the second direction.

4. The optical element of claim 3, wherein the second track is a straight line.

5. The optical element of claim 3, wherein the second track has a second period T₂And a second amplitude A₂The waveform trace of (2).

6. The optical element of claim 5, wherein the second track is a sinusoidal function or a Fourier series consisting of a plurality of sinusoidal functions, and T₂、A₂And D satisfies the following formula:

(1)A₂≥2D；

(2)T₂not less than 2D; and

(3)

7. the optical element of claim 6, wherein

8. The optical element of claim 3, wherein the first track is at a first track pitch P along the second direction₁Are arranged at intervals, and 0.1D is less than or equal to P₁Less than or equal to 25D; and the second track has a second track pitch P along the first direction₂Are arranged at intervals, and 0.1D is less than or equal to P₂≤25D。

9. The optical element of claim 8, wherein

10. The optical element of claim 1, 3 or 4, wherein the light-deflecting regions each comprise two or more periodic diffractive structures.

11. The optical element of claim 1, 3 or 4, wherein the light-deflecting regions each comprise a diffraction structure of two or more amplitudes.

12. The optical element of claim 1, 3 or 4, wherein the light-deflecting regions each comprise a diffractive structure arranged with at least one of a graded period and a graded amplitude.

13. A display device, comprising:

a display; and

the optical element of claim 1, disposed on a light exit side of the display.